Lubricating oil compositions and improvement agents therefor



Patented July 12, 1949 LUBRICA'I'ING OIL COMPOSITIONS AND IIWPROVEMENTAGENTS THEREFOR Herschel G. Smith, Walling'ford, and Troy L. Cantrell,Lansdowne, Pa., assignors to Gulf Oil Corporation, Pittsburgh, Pa.,

Pennsylvania a corporation of No Drawing. Application September 24,1946,

Serial No. 699,092 7 2 Claims.

This invention relates to lubricating oil compositions and improvementagents therefor, and more particularly, to improved detergentlubricating oil compositions having antioxidant properties which arecapable of suspending gums, resins, carbon and varnish-like materialswhich are formed on the pistons and rings of internal combustionengines.

Petroleum lubricating oils, and some compounded oils, are prone todeteriorate under the conditions existing in internal combustionengines, with development of resinous products, ultimately resulting insludging, ring sticking, and varnishing, which lower the efiiciency ofthe motor. There is also a tendency to form so-called separable sludge,which settles in the crankcase with undesirable effects.

It is well known to incorporate various metal soaps (metallo-fatty acidcompounds) as well as other additives in oils to improve the oils inthese and other respects. There are difiiculties in incorporating thesenormal soaps and in keeping them dispersed in oils in stable condition;and moreover, it often happens that a very small amount of soap producesa considerable change in the viscosity of an oil. For example, a limesoap prepared in the ordinary wet way can be dissolved in oil, but evensmall amounts tend to thicken the oil. The moisture present in the soapassists in the production of a colloidal soap dispersion or gel, but atthe same time it results in an excessive viscosity. Such a lime soap isdiflicult to dehydrate and the dry soap is a hard material which is verydifficult to work into mineral oils. Furthermore, in some instances, theordinary soaps accelerate oil oxidation, thus necessitating the additionof a separate antioxidant compound to the composition.

It is an object of this invention to provide a new improvement agent formineral lubricating oils, which will improve the detergent qualities ofthe oils in reducing ring sticking, carbon deposition and the formationof separable, sludge without excessively increasing the viscosity of theoils, and which, at the same time, will act as an antioxidant andoiliness agent.

It is a further object of this invention to provide new detergentlubricating oil compositions having improved antioxidant and oilinessproperties.

These and other objects are achieved by the present invention wherein weprovide an anhydrous, non-hygroscopic improvement agent comprising thelime saponification products of a sperm oil. Such an agent, prepared inaccordance with the methods of our invention, is soluble in a widevariety of mineral lubricating oils and is effective, even in smallamounts, in imparting to mineral lubricating oils improved detergent,antioxidant and oiliness properties. We consider mineral lubricatingoils containing such an agent as part of our invention.

More particularly, our new improvement agent is an anhydrous,non-hygroscopic mixture of sperm oil alcohols and the calcium salts ofsperm oil fatty acids, and is derived from a sperm oil by saponificationthereof with lime. While we do not desire to be limited to any theory ofthe action of the individual components of our new improvement agent, itis our present belief that the free sperm oil acohols act to prevent thecalcium salts of the sperm oil fatty acids from solidifying, therebymaintaining the agent as a whole in a fluid condition readily soluble inmineral oils. In fact, as is set forth hereinafter, it is possible toprepare stable concentrates of the agent in mineral oils which containas much as 50 per cent by weight of the agent.

As indicated in U. S. Patent No, 2,179,066 to Smith, sperm oil iscomposed principally of the higher molecular weight unsaturatedaliphatic monohydric alcohol esters of the higher molecular weightunsaturated fatty acids. The unsaturated character of sperm oil and itsother characteristics are fully set forth in the patent. The reactionproduct secured by the saponification of sperm oil with lime inaccordance with our invention does not have the normal characteristicsof a calcium soap of an ordinary fatty acid, such as calcium oleate orcalcium stearate. The reaction product is a thick liquid, and aspreviously stated, dissolves readily in a mineral oil withoutappreciably affecting the viscosity of the oil. Furthermore, the efiectsof the use of this material in a mineral oil are diiierent from thosesecured from the addition of a corresponding amount of an ordinarycalcium soap, particularly in regard to viscosity, solubility,antioxidant and oiliness effects.

Sperm oil often contains some glycerides, and since the preparation ofour new improvement agent involves a saponification, any glyceridespresent will yield free glycerol. If the glycerol were allowed to remainin the agent, serious corrosion difficulties would be encountered in theuse of lubricating oil compositions containing the agent. This is due tothe facts that (1) glycerol is hygroscopic and absorbs moisture, and (2)under service conditions, glycerol itself breaks down into compoundswhich are corrosive. Accordingly, it is an important feature of ourinvention that our new improvement agent be both anhydrous andnon-hygroscopic. 'To this end, any glycerol and/or water formednorpresent in the saponification product are removed. The formation ofglycerol during the -.saponification may be entirely avoided by using.as a starting material a purified sperm oil which contains noglycerides.

The saponification of a sperm oil in accordance with our invention isconveniently accomplished by reacting the sperm oil with lime atanelevated temperature. Either quicklime or slaked lime, that is calciumoxide or calcium hydroxide may be employed. If quicklime is used, somewater, say l8lparts of water-per 56 parts of quicklime is added in orderto accelerate the saponification reaction. In any event, the lime ispreferably employed in slight excess of the amount theoreticallyrequired'to react with all of the fatty acids liberated in thesaponification of the sperm oil, an excess of about'5 per 'cent beingsuitable. Generally, the amount of lime used ranges from 7.5 per'cent'to11 percent 'by 'weight'of the'sperm oil. Any unreactedexcess'of lime isremoved by filtering. Accordingly, the saponification product obtainedis a mixture 'of sperm oil alcohols and the calcium salts of sperm oilfatty acids, the fatty acids in the form-of their calciumsalts and thesperm oil alcohols existing in the-same relative proportions as thecorresponding alcohols and acids exist in the unsaponifiedsperm oil.

The temperatures employed-for the. saponificationmay range from 440.F.;to'550.E. Temperatures much above 550 should -be avoided because atsuch .temperaturespyrolysis ofthessperm oil fatty acids may :takeiplace.Glycerol, which may be encountered in small amounts, boils .at a highertemperature, viz., 554 but at the temperatures of the saponification,glycerol and water are distilled off completely as an azeotropic mixturewith some of the sperm oil alcohols. About hours heating usuallysuffices for the complete saponification of the sperm oil and thecomplete removal of glycerol and water. If desired, the removal of theglycerol may be expedited by steam distilling the reaction mixture inthe later stages of reaction orafter the saponification is complete.After all the glycerol has been distilled oh, the condensate from thedistillations separate into two layers, a lower layer containingglycerol and water and an upper layer of substantially pure sperm oilalcohols. The sperm oil alcohols are-separated, dried and returned tothe reaction mass remaining in the reaction vessel,

In an especially good embodiment of 'the invention, the sperm oil isdiluted with a mineral oil prior to saponification. Conducting thesaponification in the presence of mineral .oil reduces the consistencyof the reaction products, and the resultingconcentrateiof agent inmineral oil may be blended withmin'eral lubricating oil in the intendedultimate proportion with very little equipment, little effort, andwithout heating the oil in which the concentrate is to be blended. Inconducting the saponification in the presence of a mineral oil, it isconvenient to use approximately equal proportions by weight of the spermoil and mineral oil, but higher proportions of mineral oil, as high as 3parts of mineral oil to 1 part of sperm oil or higher, mayadvantageously be employed. It is desirable to employ for this purposeamineral oil of substantially similar quality as the mineral lubricatingoil to which the concentrate of agent is to be added, but it ispreferred to employ a naphthenic oil because of the greater solubilityof the agent in this type of oil than in a parafiinic oil.

In general, our new improvement agent is present in the "final"lubricating oil composition in-an amount sufiicient to confer improveddetergent, antioxidant and oiliness properties on the composition. Whilelarger amounts may be .used without harmful efiects, it is ordinarilysuffi'cient to employ a small amount of the improvement agent, from 0.1to 5.0 per cent by weight on the mineral lubricating oil.

The following examples are further illustrative of our invention. Unlessotherwise stated, all parts are by weight.

Example 1.One hundred parts of 45 natural winter sperm oil'were treatedwith 10 parts hydrated lime in a suitablestill andmaintained at atemperature of 500 -F. while agitating the mixture. Steam was introducedin the later stages of the reaction to distill over all the sperm oilalcohols and contaminating glycerol. The condensate'from'the stillconsisted of a lower layer containing the glycerol and water and-anupper layer of substantially pure sperm oil alcohols (which areinsoluble in water). The sperm oil alcohols were separated, dried andthen mixed with the calcium fatty acid sa'lts remaining in the'still toyield-a "liquid mass. The liquid was filtered to remove any excess lime.The resulting filtrate was an excellent improvement agent for minerallubricating oils.

As stated, there are advantages in conducting the saponificationof spermoil, and dehydration and deglycerinization of the products, in thepresence'of mineral oilas a'diluent. The mineral oil reduces theconsistency o'f'the products of the above-described saponification :andincreases the fluidity of the material was to facilitate handling andmixing with 'the lubricating oil with which the material is to beblended .to form the final lubricating oil composition. A convenientmixture for the treatment is about equal parts of sperm oil and mineral.oil. The following examples show the'use of mineral .oil in the.preparation of our new improvement agent.

Example 2.--A blend was .prepared of 50 parts of 45 natural winter spermoil .and .50 .parts .of 55 SUV/ F. naphthenetype mineral lubricatingoil. This blend was .agitated mechanically andheatedto a .temperatureof450 F., 5 .parts of lime added, and the .mixture maintained at aboutthis temperature .until the reaction was complete. The concentrate ofagent'in .the .mineral oil was cooled to about .300" and filtered toremove any excess of insolublematter or unreacted lime. The .product wasa clear liquid, readily miscible with lubricatingoils.

Example 3.In another example, the same procedure was vused exceptthat.100.SUV/l00 oil of the same'type-ibase.wassubstitutedfor the 55viscosity oil and a slightly higher reaction temperature, 480 F. wasemployed.

The following table of typical properties refers to the products ofExamples 2 and 3 as well as to the starting materials.

by adding to a Diesel lubricating oil base, for example, 4 per cent ofthe above described concen- Lime-Sapon- Lime-Sapon- 55 V15. 100 Vis 45N. W. ifled Sperm ified Sperm Description S Naphthene N aphthene perm011 Oil Ooncen- 011 Concen- 011 (on mam OilA (0113) mm in one Gravity:API 23. 24. 2 20. 2 Sp. Gr 60/60 F 0. 9123 0.9088 0. 9328 Viscosity,SUV:

100 F- 707 104 14, 839 210 F 750 39 Flash, "F Fire, 00: F...

our: F Color, NPA Copper Strip Test Neutralization N o Carbon Residue:Percent Acidity, Organic Oleic Acid Equiv. Saponification NoGlyceride-free Sperm Oil Sperm Oil Gravity: API 30. 9 29.7-28.6 Sp.Gra.: 60l60 F. 0.8713 0. 8780.884 Viscosity, SUV: 100 86. 95-100 Flash,00: F 475 490 Color, NPA, not dark 1. 0 3.0 Neutralization No., max. 0.3 2. 0 Saponification No 117. 3 120-140 Iodine N 0., Mod. Hanus 75. 575-90 Such purified sperm oil preparations are worked up in a mannerquite similar to the treatment of sperm oil.

Example 4.-A glyceride-free sperm oil preparation as described above wastreated as in Example 3, yielding a blend of equal parts of the limesaponification products and naphthenic mineral lubricating oil. Acomparison of this concentrate with the base oil is as follows:

Napthenic Lime Saponi- Type fied Mineral Glyceride-free LubricatingSperm Oil Oil Concentrate Gravity: API 24. 2 23.6 Viscosity, SUV:

100 F 276 106 3. 75 Neutralization N o 0. 48

An improved Diesel engine oil may be prepared trate. A comparison ofthis improved oil with the base oil is given below:

gg Base Oil Gravity: API 26. 2 26. 5

Sp. Gr; 60/60 F 0.8973 0.8956 Viscosity, SUV:

Copper Strip Test 212 F passes passes Motor Service Test 1 PistonRating. l 4

Almen Test: Lb 8 6 Tlmken Test, Special: Lb 16 14 1 See U. 8. Patent N0. 2,179,067, page 6.

' desirable to improve the color of the agent. This decolorization maybe accomplished in known manner by treatment with a small quantity ofdecolorizing material such as fullers earth, decolorizing clay,activated alumina, activated carbons or activated silicates.

As shown in the preceding disclosure, lubricating oil compositionscontaining our new improvement agent possess excellent detergentproperties. Thus, any gums, resins, carbon and varnish-like materialswhich tend to form on the pistons and rings of internal combustionengines are suspended and not deposited. Furthermore no separable sludgeis formed. In addition to conferring detergent properties, our newimprovement agent provides enhanced oiliness characteristics to minerallubricating oils, and is a good antioxidant in itself. The agent issimply and cheaply prepared, and its excellent solubility in mineraloils not only enables the convenient preparation of its blends withmineral lubricating oils, but insures that the agent will not separateout from the oils either in storage or use. Notwithstanding the factthat our new agent contains the calcium salts of sperm oil fatty acids,the effect of our agent on the viscosity of lubricating oil compositionsis negligible.

What we claim is:

1. An improved liquid lubricating oil composition comprising a minerallubricating oil and an anhydrous, non-hygroscopic mixture of sperm oilalcohols and the calcium salts of sperm oil fatty acids, the fatty acidsin the form of their calcium salts and. the sperm oil alcohols existingin substantially the same relative proportions as the correspondingalcohols and acids exist in the unsaponified sperm oil, and beingpresent in an amount suflicient to confer improved detergent,antioxidant and oiliness properties to the composition.

2. An improved liquid lubricating oil composition comprising a minerallubricating oil and from 0.1% to 5% by Weight based on the mineral oilof an anhydrous, non-hygroscopic mixture of sperm oil alcohols and thecalcium salts of sperm oil fatty acids, the fatty acids in the form oftheir calcium salts and the sperm oil alcohols existing in substantiallythe same relative proportions as the corresponding alcohols and acidsexist in the unsaponified :sperm oil, said composition having improveddetergent, antioxidant and oiliness properties.

HERSCHEL G. SMITH. TROY L. CANTRELL.

REFERENCES CITED The "following referenlces are of record in the file ofthis patent:

UNITED :STATES PATENTS Number Name Date 1,912,001 Lauer May 30, 19332,108,643 Brunstrum Feb. 15, 1938 2,148,292 Francis May 30, 19392,319,405 Ittner May 18, 1943 2,329,474 Lazar Sept. 14, 1943 2,356,340Murphree Aug. 22, 1944 2,393,421 Schmidt Jan. 22, 1946 2,417,428McLennen Mar. 18, 1947 2,417,432 McLennen Mar. 18, 1947 OTHER REFERENCESLubricating Greases, Klemgard, 1937, Reinhold Publishing Company, N. Y.,page 60.

Fats and Oils, Kirschenbauer, 1944, Reinhold Publishing Company, N. Y.,page 121.

